🔍 Key Concepts

• Degrees of freedom of ship motion (surge, sway, heave, roll, pitch, yaw) • Difference between linear (translational) motion and rotational motion of a vessel • How motion is described relative to the ship’s longitudinal, transverse, and vertical axes

💭 Think About

• Which term describes a motion that moves the whole vessel straight up and down, without tilting the bow or stern? • Look at the other choices: which ones are associated with rotation about an axis (like nodding or twisting) rather than straight-line movement? • Think about the three main directions a ship can move: forward/backward, side-to-side, and up/down. Match each common term to one of those directions.

✅ Before You Answer

• Identify which axis is vertical and which motion is along that axis rather than around it • Separate the terms that describe rotational motion from those that describe straight-line (translational) motion • Confirm that your choice specifically matches an up-and-down vertical displacement of the vessel’s center of mass